Always use a color table with 256 colors

Speculative fix for skbug.com/5883

We are hitting an assert (which I have not been able to repro - still
need to get the skp that triggers it) because we are trying to read
beyond the end of the color table. We use 8-bit indices, so 256 should
be enough to prevent going beyond the end. There is only one case when
we use a smaller color table - when it is a dummy. Make the dummy full
size.

NOTREECHECKS=true

BUG=skia:5883
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2452673002

Review-Url: https://codereview.chromium.org/2452673002
This commit is contained in:
scroggo 2016-10-25 12:48:25 -07:00 committed by Commit bot
parent e9db0b7f0e
commit 0057ac11fc

View File

@ -37,6 +37,7 @@
#include "SkGifCodec.h"
#include "SkStream.h"
#include "SkSwizzler.h"
#include "SkUtils.h"
#include <algorithm>
@ -143,9 +144,10 @@ void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, size_t frameIn
fCurrColorTable = fReader->getColorTable(dstInfo.colorType(), frameIndex);
fCurrColorTableIsReal = fCurrColorTable;
if (!fCurrColorTable) {
// This is possible for an empty frame. Create a dummy with one value (transparent).
SkPMColor color = SK_ColorTRANSPARENT;
fCurrColorTable.reset(new SkColorTable(&color, 1));
// This is possible for an empty frame. Create a dummy with all transparent.
SkPMColor colors[MAX_COLORS];
sk_memset32(colors, SK_ColorTRANSPARENT, MAX_COLORS);
fCurrColorTable.reset(new SkColorTable(colors, 256));
}
if (inputColorCount) {